Elpidium O. F. Müller, 1880

Pereira, Julia S., Rocha, Carlos E. F. & Pinto, Ricardo L., 2019, On three new species of Elpidium Müller, 1880 and the re-description of Elpidium laesslei (Tressler, 1956) from Jamaica (Ostracoda: Podocopida: Limnocytheridae), Zootaxa 4604 (1), pp. 103-140 : 105-122

Genus Elpidium O. F. Müller, 1880

Type species: Elpidium bromeliarum O. F. M̹ller, 1880

Species included in the genus: Elpidium maricaoensis ( Tressler, 1941) ; Elpidium laesslei ( Tressler, 1956) ; Elpidium inaequivalvis Danielopol, 1980 ; Elpidium pintoi Danielopol, 1980 ; Elpidium purperae Danielopol, 1980 ; Elpidium merendonense Pinto & Jocqué, 2013 ; Elpidium martensi Danielopol et al., 2014 ; Elpidium littlei n. sp.; Elpidium heberti n. sp.; Elpidium wolfi n. sp.

Diagnosis (modified after Pinto & Jocqué 2013). Medium to large sized carapace, generally with subtle ornamentation, marked by minute foveolae (with the exception of Elpidium laesslei ) and brownish color; width larger than height, ventral surface flat. Bisexual, generally with sexual dimorphism present on both carapace and appendages; males with greatest width usually at mid-length; females broader than males posteriorly, due to the existence of a brooding chamber, and greatest width displaced posteriorly. Antennula five-segmented. First segment bearing dorso-apical expansion set with pseudochaetae; Antenna with 2 biserrate claws and 1 pectinate claw in males and 3 biserrate claws in females; terminal segment of antenna bearing hyaline formation in both males and females; Maxillula with two spatulate claws in each second and third endites; copulatory process a hook-like structure placed near distal lobe of hemipenis, distal lobe and dorsal seta, both variable in shape and size.

Elpidium littlei n. sp.

(Figs. 1–7)

urn:lsid:zoobank.org:act:E0038144-215E-482C-A9C1-B7ED46F24189

2014 Elpidium sp.1—Danielopol et al.: 90, 94, 122, 123, figures 17, 19, 25

Diagnosis. Carapace surface brownish with sparse setae, normal pore canals and subtle ornamentation consisting in individual foveolae. Sexual dimorphism in carapace very pronounced: posterior end, in dorsal view, acuminated in males while rounded in females. In dorsal and ventral views carapace elongated (length/width c. 1.3) and symmetric. In right lateral view, dorsal margin slightly arched, ventral margin straight and flange absent. Right and left distal lobes of hemipenis symmetric, quadrate (length similar to width), with no digital expansion and bearing tiny dorsal seta. Lower ramus long, slender and sinuous in its apex. Copulatory process wrapped into a fold of the muscular body and consisting in separated and clearly distinguishable ejaculatory duct and distal glans. Ejaculatory duct thin, short and abruptly curved on its apex. Distal glans greatly larger than ejaculatory duct and rounded on its apex.

T ype material. Holotype: a dissected male (MZUSP 37371) with valves dried and coated for scanning electron microscopy stored in a micropaleontological slide and appendages mounted on a glass slide with CMC-9AF mounting medium. Allotype: a dissected female ( MZUSP 37372 ) stored like the holotype. Paratypes: four males ( MZUSP 37373 , MZUSP 37381 , MZUSP 37383 , MZUSP 37384 ) dissected and stored like the holotype; six males ( MZUSP 37375 , MZUSP 37376 , MZUSP 37377 , MZUSP 37379 , MZUSP 37380 , MZUSP 37382 ) and a female ( MZUSP 37374 ) dried and coated for scanning electron microscopy stored in micropaleontological slides; a female (MZUSP 37378) dissected with appendages mounted on a permanent slide with CMC-9AF mounting medium; one juvenile, eight males and 12 females kept whole in a vial with 70% ethanol ( MZUSP 37385 ) .

Type locality. Tank-bromeliads from Good Hope, Jamaica. Approximate geographical coordinates: 18°25' N, 77°41' W. Material collected in 2 Mar. 1991 by Paul D. N. Hebert .

Derivation of name. The species is named in honour of Professor Tom J. Little (Institute of Evolutionary Biology, University of Edinburgh, Scotland, UK) in recognition of his remarkable contribution to the knowledge about Jamaican Elpidium .

Description of male. Carapace (Fig. 1). Medium-sized carapace (length= 0.7 mm). Color varying from light to dark brown. Subtle ornamentation as numerous minute and individual foveolae. Normal pore canals and sparse setae all over the carapace. In dorsal and ventral views, carapace elongated with acuminate end; with antero-ventral

Right valve ( Fig. 2 A–C). Selvage well-marked in anterior, ventral and posterior margins; bow funnel-shaped structure in oral region. Flange in anterior, ventral and posterior margins, the latter one with sparse setae. Reduced vestibule on both anterior and posterior regions. Hinge elongated, occupying almost all length of dorsal margin; cardinal bar with two proto-teeth, posterior one more pronounced. Adductor muscle scars four stacked spots.

Antennula ( Fig. 3 A–C, 4A). Five-segmented. First segment relatively long bearing sub-apical expansion with tuft of tiny pseudochaetae. Second segment the longest, with a unique plumose seta in ventro-apical position and reaching fourth segment. Third segment small, almost square with a unique serrate seta in dorso-apical position that reaches the fourth segment at about mid-length. Fourth segment bigger in length than in width and partially subdivided slightly before mid-length, with two

serrate dorso-apical setae with similar lengths, serrate ventro-apical seta and ventro-apically a very long serrate seta and three serrate dorso-apical setae, two short and one long, approximately as long as ventro-apical seta. Fifth segment (terminal) with three serrate and thin setae, one long and two short and equal in length, plus one aesthetasc (Ya). The third, fourth and fifth segments each with a row of pseudochaetae that covers the whole or part of their apical portions. All setae with constrictions.

Antenna ( Fig. 3 D–H, 4B). Protopodite with two segments: coxa ring-shaped and basis long and arched, dorsally with two rows of tiny pseudochaetae and one group of pseudochaetae in triangular shape. Endopodite with three segments: first one relatively short, with very long serrate seta in ventro-apical position whose basis is on an expansion of the segment and apex reaches second segment apical portion; ventrally with a group of pseudochaetae in triangular shape and dorsally three separated groups of long pseudochaetae, with each group reaching base of next one in length. Second segment long with length greater than width, bearing two dorso-apical setae, one half as long as the other, serrate seta and aesthetasc (Y) in ventro-medial position and apically, two setae: one long, strong and serrated, and one minute. Third segment (terminal) with three claws of equal length, two serrated and one pectinate with a very strong row of denticles, besides tiny seta and hyaline formation. Exopodite very long and arched spinneret seta and very small seta.

Mandible ( Fig. 3I , 4C ). Coxa internally with eight strong teeth, modified X1 seta (spoon-shaped) and long plumose seta plus two interdental setae (X2 and X3), three interdental spines and sub-apical plumose seta. Palp foursegmented: basis and three-articulated endopodite; basis with two setae in subapical position and respiratory plate (the exopodite) with three long setae and one short, reflexed seta, all with tiny setules; first endopodial segment with two apical setae, one half as long as the other; second endopodial segment with four apical setae, two long and two short; third endopodial segment (terminal) with three setae, two thin and equivalent in length, and one larger and longer than the other two.

Maxillula ( Fig. 3 J–L, 4D). Bearing three endites. First one with three slender setae equal in length; second and third endites with two spatulate claws and three smooth and slender setae each. Palp with four rows of tiny pseudochaetae medially-positioned and two long plumose setae equal in length plus very short vestigial seta on its apical portion. Respiratory plate (exopodite) well developed with several tiny spines on its body and 16 rays plus one reflexed seta, each with several setules.

First thoracic limb ( Fig. 5A , 6 A–C). Basis long and slightly arched with several rows of tiny pseudochaetae. Dorsal margin with medium-sized plumose seta plus two short apical pappose setae wrapped in their basal portion by an expansion of segment. Exopodite a long and plumose seta. Endopodial portion three-segmented with length greater than width. First segment the longest one with several long pseudochaetae in both sides and a unique and strong biserrate seta, slightly shorter than second segment length; second segment with no setae and third segment (terminal) with strong and arched claw, slightly biserrate on its end and with vestigial seta and row of pseudochaetae on its basis. All endopodial segments with rows of pseudochaetae in their apical and lateral portions.

Second thoracic limb ( Fig. 5B , 6D, E ). Overall, similar to the first thoracic limb. Total appendage length greater and basis with only one plumose seta on its apical portion, also wrapped by an expansion of segment, but incompletely. Biserrate seta of the first endopodial segment and second segment equally long. Third segment (terminal) with strong apical claw, slightly longer and more arched than claw present on first thoracic limb terminal segment.

Third thoracic limb ( Fig. 5C , 6F, G ). Basis with three setae: two slender setae on the dorsal margin, one in medial and one, pappose, in apical position, plus one plumose exopodial seta on ventral margin in medio-proximal position. All three endopodial segments with length greater than width and their total lengths greater than in the two anterior thoracic limbs. First segment with a unique biserrate seta equal in length to second segment and a little slenderer than its homologous structure in first and second thoracic limbs; second segment with transversal row of pseudochaetae on its lateral portion (a structure nonexistent on first and second thoracic limbs) and no setae; third segment (terminal) with extremely long and thin claw with vestigial seta on its basis. This latter structure biserrate as in first and second thoracic limbs, but not only in its end but in approximately 2/3 of its length. All three endopodial segments with rows of pseudochaetae in their apical and lateral portions which are longer than those of two anterior thoracic limbs.

Hemipenis ( Fig. 5E, F , 6 H–J). Large, sclerotized and rounded muscular body. Three muscular bundles move different elements of the hemipenis: copulatory complex and distal lobe. First one medially placed and formed by copulatory process and lower ramus. Copulatory process with large basis and tapering towards the apex, divided into ejaculatory duct and distal glans. Ejaculatory duct thin, short, with abruptly curved apex. Distal glans longer than ejaculatory duct and not so thin, with rounded apex. Both structures wrapped in fold of the muscular body. Lower ramus long, thin and sinuous apically. Distal lobe quadrate with similar length and width and with no digital expansion. Dorsal seta very small and slender. Furcal lobes two pairs of short setae set with numerous pseudochaetae.

Additional description of female. Carapace ( Fig. 2 G–L, 7). Relatively small-sized carapace (length= 0.76 mm). Elongated in dorsal, ventral and right lateral views. In dorsal view, greatest width placed slightly after mid-length. Left valve overlapping right valve on all margins. Posterior region larger than in males, due to the presence of a brooding chamber, and rounded.

Antenna ( Fig. 4E ). Terminal segment with tiny seta, hyaline formation and three biserrate claws with approximately equal lengths, as opposed to males which have two biserrate claws and one pectinate claw.

Abdomen ( Fig. 5D ). End of body large and rounded, with medial stiff spine-like seta, female genital lobes and furcal lobes. Female genital lobe rounded and rigid, internally with trabeculae. Furcal lobe rounded but not rigid, with three setae and numerous pseudochaetae.

Comparison to other Elpidium species. Elpidium littlei n. sp. presents on the carapace a high degree of sexual dimorphism—as detailed above—following in this way the usual pattern for the genus. However, its carapace morphology is different when compared with species already described as Elpidium bromeliarum or Elpidium martensi , for example. Males and females have the end of their bodies respectively acuminate and rounded instead of rounded and truncate, as it is usually described for Elpidium species known so far. This species also differs from any other Elpidium species by the copulatory process morphology. It is divided in distal glans and ejaculatory duct, both easily recognized, a characteristic unknown for the genus until now and which was observed solely for the species described in the present work. Its morphology is relatively similar to that observed for Elpidium heberti n. sp., but the two species can be easily distinguished from one another by the distal lobe morphology on the hemipenis—quadrate with no digital expansion in Elpidium littlei n. sp. and acuminate with short and pointed digital expansion in Elpidium heberti n. sp. —and by the carapace morphology, which is acuminate for both males and females in Elpidium heberti n. sp.

Elpidium heberti n. sp.

( Figs. 8–13 )

urn:lsid:zoobank.org:act:272989E0-7C20-46B6-8210-F6F62B90B10E

2014 Elpidium sp.2—Danielopol et al.:90, 111, 121, 123, figures 17, 19, 25

Diagnosis. Carapace surface brownish with sparse setae, normal pore canals and subtle ornamentation consisting in foveolae arranged in groups. Sexual dimorphism in carapace present but subtle: posterior end acuminate both in males and females. In dorsal and ventral views, carapace elongated (length/width c. 1.3) and asymmetric. In right lateral view, dorsal margin greatly arched, ventral margin straight and external antero-ventral flange absent. Distal lobe of hemipenis symmetric, acuminate (length superior to width) with short digital expansion and bearing short dorsal seta on ventral side. Lower ramus short with rounded apex. Copulatory process wrapped in fold of muscular body and consisting in separated and clearly distinguishable ejaculatory duct and distal glans. Ejaculatory duct thin, short and slightly curved on its apex. Distal glans greatly larger than ejaculatory duct and globular on its apex.

Type material. Holotype: a dissected male ( MZUSP 37386 ) with valves dried and coated for scanning electron microscopy stored in micropaleontological slides and appendages mounted on a permanent slide with CMC-9AF mounting medium . Allotype: a dissected female ( MZUSP 37387 ) with valves dried and coated for scanning electron microscopy and stored in micropaleontological slides and appendages mounted on a permanent slide with CMC-9- AF mounting medium . Paratypes: a male ( MZUSP 37388 ) and two females ( MZUSP 37391 , MZUSP 37395 ) dissected and stored like the holotype; two males ( MZUSP37389 , MZUSP 37393 ) and two females ( MZUSP 37390 , MZUSP37394 ) dried and coated for scanning electron microscopy and stored in micropaleontological slides; a male ( MZUSP 37392 ) dissected with appendages mounted on a permanent slide with CMC-9AF mounting medium; two males and five females kept whole in a vial with 70% ethanol ( MZUSP37396 ) .

Type locality. Tank-bromeliads from Sherwood forest , Portland, south-east from Port Antonio, Jamaica. Approximate geographical coordinates 18°08'N, 76°22'W. Material collected on 26 Mar. 1991 by Paul D. N. Hebert .

Derivation of name. The species is named in honour of Professor Paul D. N. Hebert (Centre for Biodiversity Genomics, University of Guelph, Canada) in recognition of his remarkable contribution to the knowledge about Jamaican Elpidium .

Description of male. Carapace ( Fig. 8 ). Large-sized carapace (length= 0.86 mm). Surface brownish, and filled with sparse setae and normal pore canals. Ornamentation subtle, composed of minute foveolae arranged in groups. In dorsal and ventral views, carapace elongated and posterior region markedly acuminate. Dorsal and ventral margins straight in dorsal and ventral view, respectively. In right lateral view, carapace also elongated, with dorsal margin greatly arched and left valve overlapping right one on all margins.

Left valve ( Fig. 8 J–L). Selvage well-marked along all valve margin, forming bow funnel-shaped structure on oral region. Flange present, and well developed in anterior, ventral and posterior regions, bearing small sparse setae in posterior portion. Vestibule present in both anterior and posterior margins.

Right valve ( Fig. 8 M–O). Selvage well-marked along all valve margin, forming bow funnel-shaped structure on oral region. Flange present and well developed in anterior, ventral and posterior margins, latter one bearing small sparse setae. Vestibule present in both anterior and posterior regions. Hinge consists of bar with two proto-teeth, posterior one more pronounced. Adductor muscle scars four stacked spots.

Antennula ( Fig. 9A , 10 A–D (represented by female specimen)). Five-segmented. First segment relatively long, sub-apically expanded, with tuft of tiny pseudochaetae. Second segment the longest one, with single plumose seta in ventro-apical position that reaches fourth segment. Third segment small and subquadrate with single serrate seta in dorso-apical position that reaches the fourth segment at about mid-length. Fourth segment bigger in length than in width and partially subdivided slightly before mid-length, with two serrate dorso-apical setae about equally long, serrate ventro-apical seta and apically very long serrate ventro-apical seta and three serrate dorso-apical setae: two short and one long with length equivalent to that of ventro-apical seta. Fifth segment (terminal) with three serrate and thin setae, a long and two equally short setae, plus aesthetasc (Ya). The third, fourth and fifth segments each with a row of pseudochaetae on at least part of their apical portions. All setae with constrictions.

Antenna ( Fig. 9B ). Protopodite with two segments: ring-shaped coxa and long and arched basis dorsally with two rows of tiny pseudochaetae and triangular-shaped group of pseudochaetae. Endopodite divided in three segments. First one relatively short, ventrally with very long serrate seta, reaching tip of second endopodial segment, and inserted in apical expansion of segment margin, plus a group of pseudochaetae, and, dorsally, three separated groups of long pseudochaetae. Second segment long and bearing two dorso-apical setae, one half as long as the other, serrate seta and aesthetasc (Y) in ventro-medial position and two apical setae: one long, strong and serrate and one reduced. Third segment (terminal) with three equally long claws, two serrate and one pectinate with very strong row of denticles, besides tiny seta and hyaline formation. Exopodite arched and long, bearing basal tiny seta.

Mandible ( Fig. 10J (represented by female specimen)). Coxa internally with eight strong teeth, modified X1 seta spoon-shaped, long plumose seta plus two interdental setae (X2 and X3) three interdental spines and plumose seta sub-apically. Palp divided in four segments: basis and three-articulated endopodite; basis with two setae in subapical position and respiratory plate (the exopodite) bearing three long setae and short, reflexed seta, all with tiny setules; first endopodial segment bearing two apical setae, one half the length of the other; second endopodial segment with four apical setae, two long and two short; third endopodial segment (terminal) with three setae, two thin and equivalent in length and one larger and longer than the other two.

Maxillula (not illustrated). Consisting of three endites. First one with three slender setae of the same length; second and third endites with two spatulate claws and three smooth and slender setae each. Palp with four rows of tiny pseudochaetae medially-positioned, and two long plumose setae equal in length plus one very short vestigial seta apically. The respiratory plate (exopodite) well developed with several tiny spines on its body and 16 rays plus one reflexed seta, each one of them set with setules.

First thoracic limb ( Fig. 11A , 12 A–D (represented by a female specimen)). Basis long and slightly arched, set with several rows of tiny pseudochaetae, bearing on the dorsal margin medium-sized plumose seta plus two short apical pappose setae whose basal portions are wrapped by expansion of segment. Exopodite represented by long and plumose seta. Endopodial portion three-segmented, with length greater than width. First one the longest, with several long pseudochaetae in both sides and single strong biserrate seta, slightly shorter than second segment length; second segment with no seta and third segment (terminal) with strong and arched claw, slightly biserrate on its end and bearing tiny vestigial seta and row of tiny pseudochaetae on its basis. Endopodial segments with rows of tiny lateral and apical pseudochaetae.

Second thoracic limb ( Fig. 11C , 12 E–H (represented by female specimen)). Larger than first thoracic limb, and different in having basis with plumose apical seta incompletely wrapped by expansion of segment. Biserrate seta on first endopodial segment as long as second segment. Third segment (terminal) with strong apical claw slightly longer and more arched than equivalent claw on first thoracic limb.

Third thoracic limb ( Fig. 11B , 12 I–O (represented by female specimen)). Basis with three setae: two slender on the dorsal margin, one in medial and one pappose in apical position, plus plumose exopodial seta on ventral margin in medio-proximal position. All three endopodial segments with length greater than width and their total length greater than in two anterior thoracic limbs. First segment with single biserrate seta equal in length to second segment and a little slenderer than its homologous structure on first and second thoracic limbs; second segment with transversal row of pseudochaetae on its lateral portion (absent in first and second thoracic limbs) and no setae; third segment (terminal) bearing extremely long and thin claw with minute vestigial seta on its basis. Structure biserrate as in first and second thoracic limbs, but not only in its end but in approximately 2/3 of its length. All three endopodial segments with rows of pseudochaetae in their apical and lateral portions which are longer than those of the two anterior thoracic limbs.

Hemipenis ( Fig. 11D ). Large and sclerotized muscular body. Main appendage elements: copulatory complex (copulatory process plus lower ramus) and distal lobe. Copulatory process similar to Elpidium littlei n. sp. with ejaculatory duct and distal glans separated and clearly distinguishable; basis broad and apex with short, thin and slightly curved ejaculatory duct and much longer distal glans with globular tip. Copulatory process wrapped in fold of the muscular body. The other component of copulatory complex, lower ramus, with distinctive shape, being relatively short, evidently less slender than what is observed on other Elpidium species and with apex more rounded than sinuous. Distal lobe with length greatly superior to width and apex markedly acuminate. Distal lobe basis with short and pointed digital expansion. Dorsal seta slender and relatively short considering total length of distal lobe. Furcal lobe bearing two pairs of slender setae filled with numerous pseudochaetae.

Additional description of female. Carapace ( Fig. 13 ). Large-sized carapace (length= 0.93 mm). Dimorphism subtle, with posterior region of female slightly broader than in males, due to the existence of brooding chamber, but posterior end of carapace acuminated in a very similar way to male specimens. Smaller valve presenting little sinuosity on posterior region, absent in males. In right lateral view, dorsal margin extremely arched, ventral margin straight and left valve overlapping right one on all margins.

Antenna ( Fig. 9C , 10 E–I). Similar to that observed in male, but terminal segment with tiny and thin seta, hyaline formation and three biserrate claws with approximately equal length instead of two biserrate claws and one pectinate claw as in males.

Abdomen ( Fig. 11E ). Female end of body rounded and large, containing spine-like seta, female genital lobes and furcal lobes. Spine-like seta rigid and placed dorso-medially on end of body. Female genital lobe rounded and rigid structure filled internally with trabeculae. Furcal lobe also rounded but not rigid, bearing three setae and completely covered with numerous pseudochaetae.

Comparison with other Elpidium species. Unlikely most of Elpidium species previously described, Elpidium heberti n. sp. has a very low sexual dimorphism degree on its carapace, an unusual characteristic for the genus. The end of the body for both males and females is acuminate and females have the posterior body region only slightly broader than males, being very similar. The morphology of the copulatory process on the hemipenis is also unusual, with distal glans and ejaculatory duct separated, a characteristic only known for the species presented here. The most similar Elpidium species to Elpidium heberti n. sp. is Elpidium wolfi n. sp. —both have low degrees of sexual dimorphism on the carapace with both males and females with acuminate posterior regions. However, these two species can be distinguished by the morphology of their copulatory processes: while Elpidium heberti n. sp. has the distal glans and ejaculatory duct clearly separated and easily recognizable, Elpidium wolfi n. sp. has the distal glans large and S-shaped while the ejaculatory duct is very small and difficult to visualize. Elpidium heberti n. sp. carapace is somewhat similar to Elpidium merendonense Pinto & Jocqué, 2013 , which also has low sexual dimorphism. However, the later species has a remarkable expansion of the left valve on its posterior region that overlaps the right valve, a characteristic absent in Elpidium heberti n. sp. The two species can be distinguished also by their hemipenes. While E. merendonense has a large digital expansion on its distal lobe and copulatory process with distal glans and ejaculatory duct united, Elpidium heberti n. sp. has a short and pointed digital expansion and distal glans and ejaculatory duct separated. Mandible and maxillula of E. heberti n. sp. (not illustrated due to poor preservation) are similar to the other species described here.

Figures

FIGURE 2. Elpidium littlei n. sp., A–F, male, G-L, female. A—right valve, internal view (MZUSP 37371); B—right valve, internal view, detail of anterior region (MZUSP 37371); C—right valve, internal view, detail of posterior region (MZUSP 37371); D—left valve, internal view (MZUSP 37371); E—left valve, internal view, detail of anterior region (MZUSP 37371); F—left valve, internal view, detail of posterior region (MZUSP 37371); G—left valve, internal view (MZUSP 37372); H—left valve, internal view, detail of anterior region (MZUSP 37372); I—left valve, internal view, detail of posterior region (MZUSP 37372); J—right valve, internal view (MZUSP 37372); K—right valve, internal view, detail of anterior region (MZUSP 37372); L—right valve, internal view, detail of posterior region (MZUSP 37372). Scale bars: A, D, G, J—100 µm; B, C—50 µm; E, F, H, I, K, L—20 µm.

FIGURE 3. Elpidium littlei n. sp., male. A—antennula, terminal segment, arrow points to the constriction present on the seta (MZUSP 37380); B—antennula, second segment, arrows point to the numerous pseudochaetae present on the segment (MZUSP 37380); C—antennula, detail of the first segment, arrows point to the rows of pseudochaetae next to the sub-apical expansion structure (MZUSP 37380); D—antenna, terminal segment showing the pectinate claw, a structure present in males (MZUSP 37380); E—antenna, part of second and third endopodial segments, arrow points to the tiny vestigial seta (MZUSP 37380); F—antenna, detail of the second segment of protopodite, arrows point to the numerous rows of pseudochaetae (MZUSP 37380); G—antenna, detail of the first endopodial segment, arrow points to the group of ventral pseudochaetae in triangular shape (MZUSP 37380); H—antenna, first endopodial segment, arrows point to the three groups of pseudochaetae (MZUSP 37380); I—mandible, coxa (MZUSP 37380); J—maxillula, detail of the endites showing the spatulate claws, arrow points to their constrictions (MZUSP 37380); K—maxillula, arrow points to the constriction present on the spatulate claws (MZUSP 37380); L—maxillula, detail showing the three rows of pseudochaetae present on the palp (MZUSP 37380). Scale bars: A-H—10 µm; I, L—2 µm; J, K—1 µm.

FIGURE 4. Elpidium littlei n. sp., A-D, male, E, female. A—antennula (MZUSP 37373); B—antenna (MZUSP 37373); Cmandible (MZUSP 37373); D—maxillula (MZUSP 37373); E—antenna (MZUSP 37378). Scale bars: A, B, E—0.05 mm; C, D—0.01 mm. Ya=aesthetasc on terminal segment of antennula. Y=aesthetasc on second endopodial segment of antenna. hy=hyaline formation on terminal segment of antenna.

FIGURE 5. Elpidium littlei, n. sp., A–C, E, F, male, D, female. A—first thoracic limb (MZUSP 37373); B—second thoracic limb (MZUSP 37373); C—third thoracic limb (MZUSP 37373); D—abdomen (MZUSP 37378); E—hemipenis (MZUSP 37371); F—hemipenis, detail of copulatory complex and distal lobe (MZUSP 37371). Scale bars: A–D, F—0.05 mm; E—0.1 mm. DL= distal lobe on hemipenis. ds=dorsal seta. cop=copulatory process on hemipenis. vej=seminal vesicle. gl=distal glans. dej=ejaculatory duct. LR=lower ramus. dor=dorsal ridge. mer=medial ridge. ver=ventral ridge.

FIGURE 6. Elpidium littlei n. sp., male. A—first thoracic limb (MZUSP 37382); B—first thoracic limb, protopodite and first endopodial segment, arrows point to the pseudochaetae groups and to the expansion of the segment that involves the basis of the two setae of protopodite (MZUSP 37382); C—first thoracic limb, detail of third endopodial segment and distal claw (MZUSP 37382); D—second thoracic limb (MZUSP 37382); E—second thoracic limb, detail of protopodite and first endopodial segment, arrow points to the group of long pseudochaetae laterally placed on the first endopodial segment (MZUSP 37382) F—third thoracic limb, detail of protopodite, arrow points to the pseudochaetae that involves the protopodite seta basis (MZUSP 37382); G—third thoracic limb, detail of first, second and third endopodial segments, arrows point to the rows of pseudochaetae transversely placed on these segments (MZUSP 37382); H—hemipenis (MZUSP 37382); I—hemipenis, detail of distal lobe lower ramus and copulatory process (MZUSP 37382); J—hemipenis, detail of copulatory process, arrows point to the union between ejaculatory duct and distal glans (MZUSP 37382). Scale bars: A, D—50 µm, B, C, E-I—20 µm, J—10 µm.

FIGURE 8. Elpidium heberti n. sp., male. A—dorsal view (MZUSP 37389); B—dorsal view, detail of anterior region (MZUSP 37389); C—dorsal view, detail of posterior region (MZUSP 37389); D—ventral view (MZUSP 37393); E—ventral view, detail of anterior region (MZUSP 37393); F—ventral view, detail of posterior region (MZUSP 37393); G—right lateral view (MZUSP 37393); H—right lateral view, detail of anterior region (MZUSP 37393); I—right lateral view, detail of posterior region (MZUSP 37393); J—left valve, internal view (MZUSP 37386); K—left valve, internal view, detail of anterior region (MZUSP 37386); L—left valve, internal view, detail of posterior region (MZUSP 37386); M—right valve, internal view (MZUSP 37386); Nright valve, internal view, detail of anterior region (MZUSP 37386); O—right valve, internal view, detail of posterior region (MZUSP 37386). Scale bars: A, F, G, I, J, M, O—100 µm; B, C—10 µm; D—200 µm; E, H, K, L, N—20 µm.

FIGURE 9. Elpidium heberti n. sp., A, B, male, C, female. A—antennula (MZUSP 37392); B—antenna (MZUSP 37392); C—antenna (MZUSP 37387). Scale bars: A–C—0.05 mm. Ya=aesthetasc on terminal segment of antennula. Y=aesthetasc on second endopodial segment of antenna. hy=hyaline formation on terminal segment of antenna.

FIGURE 10. Elpidium heberti n. sp., female. A—antennula; B—antennula, detail of first segment, arrow points to the sub-apical expansion; C—antennula, detail of first segment, arrows point to the rows of tiny pseudochaetae; D—antennula, detail of terminal segment, arrow points to the aesthethasc (Ya) chemosensorial section; E—antenna, first segment of protopodite, arrows point to the rows of pseudochaetae; F—antenna, first endopodial segment, arrows point to the three groups of pseudochaetae; G—antenna, detail of first endopodial segment, arrow points to the group of ventral pseudochaetae in triangular shape; H—antenna, second endopodial segment, arrow points to the aesthethasc (Y) chemosensorial section; I—antenna, part of second and third endopodial segments, arrow points to the tiny vestigial seta; J—mandible. Scale bars:A—20 µm, B, C, G—2 µm; D, H—1 µm; E, F, I, J—10 µm.

FIGURE 11. Elpidium heberti n. sp., A–D, male, E, female. A—first thoracic limb (MZUSP 37392); B—third thoracic limb (MZUSP 37392); C—second thoracic limb (MZUSP 37392); D—hemipenis (MZUSP 37392); E—abdomen (MZUSP 37387). Scale bars: A–E—0.05 mm. DL= distal lobe on hemipenis. ds=dorsal seta. cop=copulatory process on hemipenis. vej=seminal vesicle. gl=distal glans. dej=ejaculatory duct. LR=lower ramus. dor=dorsal ridge. mer=medial ridge. ver=ventral ridge.

FIGURE 12. Elpidium heberti n. sp., female. A—first thoracic limb, arrow points to the numerous pseudochaetae laterally placed on the first endopodial segment; B—first thoracic limb, detail of basis, arrow points to the numerous pseudochaetae present on the segment; C—first thoracic limb, detail of part of third endopodial segment and distal claw; D—first thoracic limb, detail of the final region of the distal claw with arrow pointing to the rows of pseudochaetae; E—second thoracic limb; F—second thoracic limb, detail of first endopodial segment; G—second thoracic limb, detail of third endopodial segment and distal claw; H—second thoracic limb, detail of distal claw, arrow points to the rows of pseudochaetae involving its ending; I—third thoracic limb; J-third thoracic limb, detail of protopodite basis, arrow points to pseudochaetae present on the segment; K—third thoracic limb, detail of protopodite basis, arrow points to the tiny spines present on the segment; L—third thoracic limb, detail of protopodite basis, arrow points to the pseudochaetae that involves the protopodite seta basis; M—third thoracic limb, detail of first endopodial segment; N—third thoracic limb, detail of second endopodial segment, arrows point to the rows of pseudochatae that transect the segment; O—third thoracic limb, detail of part of third endopodial segment and the distal claw, arrows point to the rows of pseudochaetae. Scale bars: A-C, I, E, N—20 µm; D-5 20 µm; F, G—10 µm; H, L—1 µm; J, K—2 µm; I, M, O: 10 µm.

FIGURE 13. Elpidium heberti n. sp., female. A—dorsal view (MZUSP 37390); B—dorsal view, detail of anterior region (MZUSP 37390); C—dorsal view, detail of posterior region (MZUSP 37390); D—ventral view (MZUSP 37394); E-ventral view, detail of anterior region (MZUSP 37394); F—ventral view, detail of posterior region (MZUSP 37394); G-right lateral view (lost specimen); H—right lateral view, detail of anterior region (lost specimen); I—right lateral view, detail of posterior region (lost specimen); J—left valve, internal view (MZUSP 37391); K—left valve, internal view, detail of anterior region (MZUSP 37391); L—left valve, internal view, detail of posterior region (MZUSP 37391), M—right valve, internal view, detail of hinge (MZUSP 37391); N—right valve, internal view, detail of anterior region (MZUSP 37391); O-right valve, internal view, detail of posterior region (MZUSP 37391); P—ventral view, detail of ornamentation (MZUSP 37394). Scale bars: A, D, G, I, K-M: 100 µm; B, C, E, F, H, N: 20 µm; J—200 µm; O—30 µm; P—2 µm.